Rectangular slide valve for rock drills



Sept '14; 1926. 1,599,816

C. C. HANSEN RECTANGULAR SLIDE VALVE FOR ROCK DRILLS Filed May 20. 1925IN V EN TOR.

dyegdzlanden IYAS'ATTO EY Patented Sept. 14, 1926.

UNITED STATES CHARLES; C. HANSEN, 0F EASTON, PENNSYLVANIA, ASSIGNOB T0COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION-01* NEW JERSQ 31..

1,599,81t PATENT tries.

RSQLI BAN?) RECTANGULARSLIDE VALVE FOR ROCK DRILLS.

Application filed May 20, 1925.

This invention relates to fluid actuated rock drills, but moreparticularly to an int proved distributing valve construction in theform of a rectangular slide valve for controlling only the inlet to bothends of the cylinder. free exhaust being controlled by the piston.

The objects of the invention are to secure a simple quick acting slidevalve of the cur rent thrown type which may be conveniently located atone side of the cylinder and provided with a flat valve box having arectangular chamber.

Further objects of the invention will hereinafter appear and theinvention is shown in one of its preferred forms in the accompav ingdrawings, in which Figure 1 is a longitudinal sectional elevation of somuch of a rock drill as will serve to illustrate the invention,

Figure 2 is a view similar to Figure 1 showing the piston and valve in adifferent position,

Figure 3 is a horizontal sectional plan view partly broken away taken onthe line 8-3 of Figure 1 through the valve looking in the direction ofthe arrows, and

Figure 4 is a detail side elevation of the valve.

Referring to the drawings, the cylinder A is provided with thereciprocating piston B in this instance having a fluted forwardextension C. In the particular rod drill illustrated, automatic riflebar rotation is provided for the drill steel (not shown) and the riflebar is indicated at D.

The cylinder is provided with the centrally located free exhaust port Econtrolled only by the piston. Inlet ports F and G for the ends of thecylinder communicate with the rectangular recess I-I forming a valvechamber in the valve box J into which the rectangular valve K is adaptedto be inserted from the side. provision being afforded to permit thevalve to slide back and forth between the end walls L and O of saidvalve chamber which form stops and seats for the valve.

Live pressure fluid is supplied at the in let P and controlled by thethrottle valve Q in the valve boX cover R and passes through and aroundone side or the other of the valve to the ends of the cylinder accordingto the position of the valve.

The valve K is in the form of a rectan- Serial No. 31,485.

gular block of appreciably greater length than width or height, asindicated in ures 3 and 4, and the valve seats on its longer sides. Thevalve is provided with flanges S at each side formed with openings T topermit the pressure fluid to pass. The valve is also formed with ahollow central portion, in this instance, two central apertures U beingshown through the valve web V so that the pressure fluid may passthrough the valve itself and through the apertures T in both flanges atone side of the valve. The combined cross sectional area of the openingsT in the flanges at one side of the valve is less than the throat areaof the restricted portions W of the cylinder inlet passages Xcommunicating with the cylinder inlet ports F and G so that the currentof live pressure fluid tending to pass through the flange openings T asthe pressure in the passage K is reduced aids in moving the valve.

In the operation of the device, let it be assumed that the piston andvalve are in the positions indicated in Figure 1 in which the piston isstarting on its forward stroke. In such positions the live pressurefluid from the supply P passes to the valve chamber H and from thencethrough the flange openings T to the inlet port F for the rear end ofthe cylinder for driving the piston forwardly. Until the piston uncoversthe ex haust port E the valve will be subject to pressure due to thefact that live pressure fluid is present within the valve chamber H, theinlet port F and the rearward end of the cylinder. As soon as theexhaust port E is uncovered by the piston C there is a drop in pressurewithin the cylinder and the inlet port F, but no substantial drop inpressure in the valve chamber I-I itself, this unbalanced conditionbeing accentuated by the fact that the cross sectional area of the open-I ings T in the flange is less than the throat area of the portion IV ofthe port F, as previously stated. This unbalanced condition of thevalve, taken in conjunction with the presence of air trapped in theforward end of the cylinder and acting upon the opposite end face of thevalve through the passage G, will shift the valve to the position shownin Figure 2, closing off the supply of pressure fluid to the rearwardend of the cylinder and admitting pressure fluid to the forward end ofthe cylinder for driving the piston rearwardly.

Owing to the fact that the valve is of reetangular shape the seatingsurfaces 011 the longer sides of the valve have a longer length than ifthe valve Was circular or of the spool type having substantially thesame total valve surface area subjected to pressure. For this reason thevalve may have a ma,- terially less travel for the same opening obtained for the spool valve, which adds to the etliciency of the valvesince the minimum travel possible with a given valve opening is highlydesirable.

I claim:

A fluid actuated rock drill, connarising a cylinder and reciprocatingpiston, a free exhaust port located centrally of the cylinder andcontrolled only by the piston, a valve box having a rectangular chamber,a dis tributing valve in the form or a rectangular block slidable insaid valve box, said valve having flanges at each end provided withopenings for the passage of live pressure fluid, cylinder inlet passagesin the valve chest, the combined cross sectional area of the openings inthe flanges being less than the throat area of the said cylinder inletpassages in the valve chestadjacent the valve, and inlet ports for theends of the cylinder controlled only by said valve.

In testimony whereof I have signed this specification.

CHARLES C. HANSEN.

